Association of BDNF / TrkB and NGF / TrkA Levels in Postmortem Brain with Major Depression and Suicide

Suicide Attempts are the main complications of Major Depressive Episodes and are difficult to predict. There is still a lack of knowledge about its neurochemical aspects. There is increasing evidence that Brain-derived neurotrophic factor (BDNF) and Nerve growth factor (NGF) play a role in the pathophysiology and treatment of depression by binding and activating cognate receptors Tyrosine Kinase B (TrkB) and Tyrosie Kinase A (TrkA), respectively. This study was conducted to examine whether BDNF and / or TrkB as well as NGF and / or TrkA expression profiles were changed in the hippocampus of postmortem brain of individuals with depression who committed suicide. This study was conducted with the brain tissue of 61 victims who died as a result of suicide due to depression and 25 people who died due to traffic accidents. The psychiatric history of the cases was determined by the psychological autopsy method. Samples were taken from the hippocampus region of the brain at the forensic medicine institution. After storage under appropriate conditions, protein and mRNA levels of BDNF, TrkB, NGF and TrkA were determined in the genetics laboratory. Average age of the suicide group was 30 and the average age of the control group was 24.5. The suicide group consisted of 70.5% male and 29.5% female cases. There was no significant difference between the groups in terms of age (p=0.062) and gender (p=0.718). BDNF, NGF, TrkA and TrkB values were found to be lower in the suicide group compared to the control group and there was a significant difference between the groups (p≤0.001; p=0.001; p=0.001; p=0.011). Given the importance of BDNF and NGF and their cognate receptors in mediating physiological functions, including cell survival and synaptic plasticity, our findings regarding decreased expression of BDNF, TrkB, NGF and TrkA in both protein and mRNA levels of postmortem brains of suicide victims suggests that it may play an important role in the pathophysiological aspects of its behavior. Further studies in this context may be useful both in understanding the molecular basis of suicide and in designing therapeutic models targeting these molecular pathways.